The present invention relates generally to applicator systems that are used to spray fluids, such as paint, sealants, coatings, and the like. More particularly, the invention relates to pressure and flow diagnostics and failure-detection for a multiple fluid spray system such as a two-component fluid spray system.
Some fluid applicators are designed to combine and spray two or more separate fluid components. A two-component system, for example, might have separate “A-side” and “B-side” fluid systems (e.g. pumps, reservoirs, and fluid lines) that carry different fluid components. These components are isolated until sprayed or otherwise applied, whereupon the components mix and chemically interact to form an application material. Two-component fluid spray systems are commonly used to apply epoxies, foams, and two-component paints. Paint systems, for example, may combine A-side paints with B-side catalyst materials. Common catalyst materials include isocyanates, polyesters, epoxies, and acrylics. Different paints or other A-side materials may require different B-side catalysts.
A- and B-side fluid systems typically comprise separate fluid sources (e.g. reservoirs or lines) that are pumped via separate pumps to a common sprayer head actuated by a human operator or an automated machine process. Many two-component spray systems use gear pumps to provide adequate spray flow. Required spray pressures vary as a function of material and application, and desired flow rates of A- and B-side fluids often differ. Paints and catalysts intended to be combined in a 10-to-1 ratio, for instance, will necessitate A-side pump displacement ten times greater than B-side pump displacement.
In many applications a single spray system may be used to sequentially apply several different materials (e.g. different paints). Before new fluid materials can be pumped and sprayed, old materials must be flushed from pumping systems to prevent contamination. Flushing can involve significant wasted material, and pump pressures and flow rates may vary as pumping begins with a new material.